To have deformed springs in one trip would take way more wieght on you RA than most of us will ever put on our trucks as personal/RV rigs. I've had trailer springs deform I the 50-70k mile range loaded at 80-100% ratings all the time. Truck springs with constant 80+% loads of gravel, soil, etc in landscape construction biz in 100k miles.
I've not seen it except 20+ years down the road in personal use rigs.
Also, remember, your trailer go to the dealer on a trailer, or more likely, pulled behind a 35 series rig with no bars. Don't worry!
Marty